1. Field of the Invention
The invention relates to voltage protection circuits used to protect devices, such as motors, from abnormal line voltages, such as low voltage conditions, which can cause damage to the device if allowed to operate with such abnormal line voltage conditions.
2. Description of the Prior Art
The prior art as exemplified in U.S. Pat. Nos. 3,663,958, 3,740,738, 3,836,790 and 3,875,463 contains a number of abnormal AC line voltage detecting circuits some of which are suitable for protecting motors against low or high line voltage conditions. Generally the prior art protection circuits have one or more deficiencies such as being excessively expensive, not being adaptable for inclusion with other protection circuits within a single protective system, being subject to excessive variation in operating characteristics, being unreliable, and the like.